Hydrocephalus shunt valve

Abstract

A valve for a shunt useable in treatment of hydrocephalus is described. The valve comprises an inlet in fluid communication with an outlet, a valve closure element, a mechanical biasing element configured to bias the valve closure element towards the inlet, and an electromechanical actuator configured to manipulate the mechanical biasing element. A biasing force applied to the valve closure element by the mechanical biasing element determines an operating pressure of the valve, and manipulating the mechanical biasing element by the electromechanical actuator allows for adjustment of the valve operating pressure by suitably varying the biasing force.

1 . A valve apparatus for a shunt useable in treatment of hydrocephalus, comprising:
 an inlet in fluid communication with an outlet;   a valve closure element and a mechanical biasing element configured to bias the valve closure element towards the inlet, wherein a biasing force applied to the valve closure element by the mechanical biasing element determines an operating pressure of the valve, the operating pressure being a minimum fluid pressure able to flow into the valve through the inlet; and   an electromechanical actuator configured to manipulate the mechanical biasing element to adjust the biasing force to vary the operating pressure of the valve.   
     
     
         2 . The valve apparatus of  claim 1 , wherein the electromechanical actuator is self-locking. 
     
     
         3 . The valve apparatus of  claim 1 , wherein the electromechanical actuator comprises a stator driven by an ultrasonic motor. 
     
     
         4 . The valve apparatus of  claim 3 , wherein the ultrasonic motor engages the stator on a surface of the stator running substantially parallel to a direction of the biasing force applied to the valve closure element. 
     
     
         5 . The valve apparatus of  claim 3 , wherein the ultrasonic motor comprises a piezoelectric element. 
     
     
         6 . The valve apparatus of  claim 5 , wherein the ultrasonic motor comprises a protrusion configured to grip the stator, the protrusion being arranged on a first surface of the piezoelectric element orthogonal to a second surface of the piezoelectric element to which voltage is applied. 
     
     
         7 . The valve apparatus of  claim 6 , wherein the protrusion is arranged to straddle a boundary between a first electrode of the piezoelectric element and a second electrode of the piezoelectric element. 
     
     
         8 . The valve apparatus of  claim 6 , wherein the protrusion comprises aluminium oxide. 
     
     
         9 . The valve apparatus of  claim 5 , wherein the piezoelectric element comprises piezoceramic material 
     
     
         10 . The valve apparatus of  claim 9 , wherein the piezoceramic material is PTZ-5H. 
     
     
         11 . The valve apparatus of  claim 3 , wherein the ultrasonic motor operates at voltage between 3 and 5 volts, inclusive. 
     
     
         12 . The valve apparatus of  claim 1 , wherein the mechanical biasing element comprises a substantially linear spring. 
     
     
         13 . The valve apparatus of  claim 12 , wherein the mechanical biasing element comprises Magnesium AZ91E-T6. 
     
     
         14 . The valve apparatus of  claim 1 , wherein the valve closure element is substantially ball shaped. 
     
     
         15 . The valve apparatus of  claim 14 , wherein a diameter of the inlet is substantially 1 millimetre ‘mm’, and a diameter of the ball shaped valve closure element is at least 1.3 mm. 
     
     
         16 . The valve apparatus of  claim 1 , further comprising a valve seat, and wherein the valve closure element is configured to rest in the valve seat. 
     
     
         17 . The valve apparatus of  claim 16  wherein a shape of the valve seat is configured to correspond to a shape of the valve closure element. 
     
     
         18 . A shunt for use in treatment of hydrocephalus comprising the valve apparatus of  claim 1 . 
     
     
         19 . A method of treatment of hydrocephalus comprising surgically implanting the shunt of  claim 18 . 
     
     
         20 . The method of  claim 19 , further comprising adjusting the operating pressure of the electromechanical actuator post-surgery.